This part proposes user-group tightness (\({\mathsf {UGT}}\) ) to seamlessly encapsulate solidarity and self-stereotyping factors, and proposes intra-group tightness (\({\mathsf {IGT}}\) ) to quantify the in-group homogeneity factor.
More concrete, given a graph \(\mathcal {G} \)  and a node pair \((v_i,v_j)\) , we use the tie strength \(w_{i,j}\)  (resp. the similarity \(\delta _{i,j}\) ) as the backbone for the solidarity factor (resp. self-stereotyping and homogeneity factors). W.l.o.g, the similarity score \(\delta _{i,j}\in [0,1]\)  is defined as the cosine similarity of the Node2Vec representations [1]} of \((v_i,v_j)\) , which is further normalized to the range of \([0,1]\)  by the min-max scaler.
In what follows, we formally define \({\mathsf {UGT}}\)  and \({\mathsf {IGT}}\)  as follows.
